1. Field of the Invention
The present invention is related to a seat hinge for a vehicle that supports the seat back of an automobile seat so that it can be folded over. More specifically, this invention is related to a seat hinge for a vehicle that supports a seat back designed to fold over forward.
2. Description of Related Art
The conventional structure of seat hinges for vehicles generally includes male brackets that are attached to seat backs of the seat, female brackets that are attached to the car body, and a pin that connects the two kinds of brackets so they pivot freely relative to each other. With this sort of structure, the seat backs of the vehicle seats are supported in a foldable manner, and can fold toward the front of the car.
Existing technology relating to this type of seat hinge includes, for example, Japanese Publicly Issued Patent Hei 2 (1990)-15410. Specifically, as shown in FIGS. 4 through 6 of that patent, the seat hinge structure described includes a center bracket (the female bracket) sandwiched between a pair of side brackets (the male brackets). These latter male brackets are supported by a pin or similar pivot so they may tilt freely. Also, the center bracket is firmly mounted to a surface of the car body by affixing screws. The pair of side brackets is also firmly mounted to the seat backs by affixing screws, in the same way as the center bracket is mounted to a surface of the car body, so that the seat backs are supported in a folding, or collapsible manner.
Another example of conventional technology relating to a seat hinge for use in vehicles is found in the report of Japanese Publicly Disclosed Patent Application Hei 8 (1996)-169266. According to this report, the structure of the seat hinge described is analogous to that shown in Japanese Publicly Issued Patent Hei 2 (1990)-15410. Specifically, a protrusion or bead extends from the female bracket where it is attached to a car body, and this bead directly contacts a male bracket support portion. The movement of the male brackets of the seat hinge is thus controlled to allow rotation toward the side of the device where the female bracket is attached to the car body. The result of this structure is that attachment components avoid obstructing the male brackets, making it easier to assemble the device.
According to these conventional designs, when a female bracket is attached to a car body, the male brackets can pivot freely around a pin. Thus, during the automobile seat assembly process, after the female bracket is firmly mounted to a car body by screws, the male brackets are free to rotate toward the car body because of their own weight. When this type of seat hinge is mounted to the vehicle, a worker performing the assembly must hold an assembly tool such as an impact driver in one hand, and align the female bracket with the car body while pressing the female bracket in place with the other hand. The worker must also hold the male brackets out of the way at the same time he presses the female bracket into place, to prevent the male brackets from interfering with the attachment devices. This structure thus results in an attachment process of the brackets to the car body that is complicated and cumbersome to carry out.
There are also disadvantages in the conventional method of attaching the male brackets to the seat backs. When the seat backs and the male brackets are assembled by being firmly attached together by screws or other fasteners, the attachment portions of the male brackets tilt towards the car body owing to their own weight. The assembly workers must align by hand the mounting parts of the attachment portions of the male brackets to the seat backs, by gripping and lifting the attachment portions of the male brackets, and aligning the mounting members of the seat backs and the male brackets. This alignment work must be performed even if the technology disclosed in Japanese Publicly Disclosed Patent Application Hei 8 (1996)-169266 is used, whereby male brackets are controlled to pivot in one particular direction with respect to the female bracket. In short, the technology described in Japanese Publicly Disclosed Patent Application Hei 8 (1996)-169266 does not teach a technique for aligning the mounting members of the attachment portions which resolves all the difficulties encountered in assembling the seats and supports.